Powerware 9150 - Manual (Page 6)

Introduction
2 Powerware ® 9150 User’s Guide
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www.powerware.com
UPS Model and Battery Configurations
There are two important considerations when selecting the UPS model
and battery configuration to properly safeguard your equipment:
: The UPS output power rating (VA) should be specified according to
the total power demand of the equipment to be protected. Some
margin should be allowed for potential expansion of the protected
system, and for possible inaccuracy in calculating or measuring the
actual power requirement.
: The battery should be sized according to the desired backup time.
The backup time is longer if the load is less than the nominal power
rating of the UPS.
Load Requirements
Determine the total load requirements, in volt-amperes (VA), of the
equipment to be protected by the UPS. The UPS load should not exceed
the UPS rating. To determine the total load requirements:
1. Obtain the load ratings from either the nameplate or operator’s
manual of the equipment to be protected by the UPS. The
ratings are listed in either watts (W), amperes or amperes max
(A), or volt-amperes.
2. If the rating is in watts, multiply by 1.4 to obtain the VA
requirement (this is the typical relationship between watts and
volt-ampere ratings in most computing equipment).
If the rating is in amperes or amperes max, multiply by the
input voltage to obtain the VA requirement.
3. Add all of the resultant VA ratings together to obtain the total
load requirements of the equipment to be protected (see
Figure 2).
3 COMPUTERS 3 MONITORS EXTERNAL
MODEM
3 x 300 WATTS X 1.4 = 1260 VA 3 x 2 AMPS x 240V = 1440 VA 50 VA
1260 VA + 1440 VA + 50 VA = 2750 VA (Total Load Requirements)
300 WATTS
EACH
2 AMPS
EACH 50 VA
Figure 2. Volt-Amperes Calculation Example